1. Temporin A and Bombinin H2 Antimicrobial Peptides Exhibit Selective Cytotoxicity to Lung Cancer Cells
Lucy Swithenbank, Phillipa Cox, Llinos G Harris, Edward Dudley, Kathryn Sinclair, Paul Lewis, Floriana Cappiello, Claire Morgan Scientifica (Cairo). 2020 Jun 26;2020:3526286. doi: 10.1155/2020/3526286. eCollection 2020.
Background: Recently, antimicrobial peptides (AMPs) have been investigated for their use in cancer therapy. They have been reported to selectively target and kill cancer cells whilst leaving normal healthy cells unaffected. Certain Anura AMPs have expressed selective cytotoxicity against tumour cells. Aim: To test the potential of Anura AMPs bombinin H2, bombinin H4, temporin A, and temporin L for use as therapeutic agents for non-small cell lung carcinoma (NSCLC). Methods: Cytotoxic effects on NSCLC cell lines A549 and Calu-3 and normal epithelial cell line Beas-2B were tested using the CellTox Green Cytotoxicity Assay. Their haemolytic effects on human erythrocytes were also tested for their clinical relevance. Cell membrane profiling, using MALDI-TOF, was performed to ascertain if membrane characteristics of the NSCLC and Beas-2B cell lines may contribute to the AMPs mode of action. Results: Bombinin H4 (100-1.5 μM, p < 0.05) and temporin A (100-50 μM, p < 0.05) showed selective cytotoxicity towards the NSCLC cell lines. Furthermore, they exhibited low levels of haemolytic activity (bombinin H4, 0.061%; temporin A, 0.874%) comparable to untreated cells. Cell membrane profiling showed the phospholipid composition of normal epithelial cell line Beas-2B to be divergent from the cancerous cell lines. However, there was an overlap in the phospholipid profiles of the NSCLC cell lines supporting the hypothesis that the AMPs may have a selective affinity via the membrane composition of cancerous cell lines. Conclusion: These results suggest that bombinin H4 and temporin A show potential for application in lung cancer therapies. Further in vitro and in vivo studies are required to develop a greater understanding of their use as anticancer agents.
2. A Temporin Derived Peptide Showing Antibacterial and Antibiofilm Activities against Staphylococcus aureus
Meidi An, Ran Guo, Shenghong Xie, Jialu Wang, Yanting Song, Rong Wang, Wenying Jiang, Shuangshuang Wei, Yingxia Zhang Protein Pept Lett. 2022 Dec 2. doi: 10.2174/0929866530666221202123011. Online ahead of print.
Background: Temporin is one family of the shortest antimicrobial peptides found in Ranidae frogs. Staphylococcus aureus is one of the main pathogens of suppurative diseases and food contamination, causing severe local or systemic infections in humans. Temporin-GHa (GHa) was previously obtained from Hylarana guentheri, showing weak antibacterial activity against S. aureus. Most temporin peptides are positively charged by arginine and lysine; however, GHa contains histidine. Objective: In order to investigate the impact of positively charged amino acid on its antibacterial and antibiofilm activity, GHa4R was designed and synthesized by replacing histidine with arginine in GHa. Method: The antibacterial activity and efficacy against S. aureus were detected by minimum inhibitory concentration, minimum bactericidal concentration, and time-killing kinetics assays. The action mechanism was determined by propidium iodide uptake and scanning electron microscopy assays. The antibiofilm activity was measured by the MTT method. Eradication of biofilm was observed by fluorescence microscope. Results: Compared to GHa, GHa4R had stronger antibacterial activity and bactericidal efficacy against S. aureus. Impressively, GHa4R presented antibacterial activity against methicillin-resistant S. aureus (MRSA). It was barely affected by temperature, pH, and storage period, showing high stability. Furthermore, it increased the permeability of the cell membrane and damaged the membrane integrity, leading to cell death. In addition, GHa4R did not induce antibiotic resistance in S. aureus in 30 days, but the MIC of vancomycin was doubled. It not only inhibited S. aureus biofilm formation but also eradicated 24 h-biofilms. Conclusion: The above-mentioned characteristics make GHa4R a promising candidate for the treatment of S. aureus infections.
3. Discovery of a Novel Antimicrobial Peptide, Temporin-PKE, from the Skin Secretion of Pelophylax kl. esculentus, and Evaluation of Its Structure-Activity Relationships
Yaxian Lin, Yangyang Jiang, Ziwei Zhao, Yueyang Lu, Xinping Xi, Chengbang Ma, Xiaoling Chen, Mei Zhou, Tianbao Chen, Chris Shaw, Lei Wang Biomolecules. 2022 May 29;12(6):759. doi: 10.3390/biom12060759.
Bacterial resistance against antibiotics has led to increasing numbers of treatment failures, and AMPs are widely accepted as becoming potential alternatives due to their advantages. Temporin-PKE is a novel peptide extracted from the skin secretion of Pelophylax kl. esculentus and it displays a strong activity against Gram-positive bacteria, with an extreme cytotoxicity. Incorporating positively charged residues and introducing D-amino acids were the two main strategies adopted for the modifications. The transformation of the chirality of Ile could reduce haemolytic activity, and an analogue with appropriate D-isoforms could maintain antimicrobial activity and stability. The substitution of hydrophobic residues could bring about more potent and broad-spectrum antimicrobial activities. The analogues with Lys were less harmful to the normal cells and their stabilities remained at similarly high levels compared to temporin-PKE. The optimal number of charges was three, and the replacement on the polar face was a better choice. Temporin-PKE-3K exerted dually efficient functions includingstrong antimicrobial and anticancer activity. This analogue showed a reduced possibility for inducing resistance in MRSA and Klebsiella pneumoniae, a rather strong antimicrobial activity in vivo, and it exhibited the highest therapeutic index such that temporin-PKE-3K has the potential to be developed as a clinical drug.
